Apologies if this has been asked before but have a question about type-specific upgrades like
Power Sword and Body Armor - These cards specifically requiring Melee characters.
If a character changes type - what happens to the upgrade?
[Source: WotC]
Traits, like Melee, are only requirements for upgrades to be attached to a character. Once attached, they stay on when a character flips between alt and bot modes.
OPBL’s ability says it triggers before defense flips, so the defender would lose that tough 3 in this scenario.